“Three‐in‐one” strategy: Heat regulation and conversion enhancement of a multifunctional separator for safer lithium–sulfur batteries

The safety problems encountered with lithium–sulfur batteries (LSBs) hinder their development for practical applications. Herein, a highly thermally conductive separator was constructed by cross-weaving super-aligned carbon nanotubes (SA-C) on boron [email protected] (SA-BC) to create composite film (SA-BC/SA-C). This used fabricate safe LSBs improved electrochemical performance. aligned structure created uniform thermal field that could rapidly dissipate heat accumulated during continuous operation due internal resistance, which prevented the of extremely high temperatures. array nitride nanosheets endowed large number adsorption sites, while graphitized nanotube skeleton accelerated catalytic conversion high-valence polysulfides into low-valence polysulfides. arrayed molecular brush design enabled regulation local current density and ion flux, considerably alleviated growth lithium dendrites, thus promoting smooth deposition Li metal. Consequently, battery SA-BC/SA-C showed good discharge capacity 685.2 mAh g−1 over 300 cycles (a decay 0.026% per cycle) at 2 C 60°C. “three-in-one” multifunctional strategy constitutes new path forward overcoming LSBs.